Embedded System is a combination of
hardware and software used to achieve a single
task. It is a computer system that monitor
respond to, or control an external environment.
Environment are connected to systems through
sensors, actuators and other I/O interfaces.
Embedded system must meet timing and other
constraints imposed on it by environment
The project aims at designing Anti-Collision System and
controlling unmanned Railway crossings. The anti-collision
system is implemented by fitting GPS receiver in each train.
Each train will compare the GPS co-ordinates sent by the
neighboring trains with its own GPS co-ordinate system. When
the difference between the trains coming in same GPS co-
ordinate reaches minimum level, then both trains will stop.
When the train reaches the spot where the IR sensors are
placed the close command for gate control system is activated.
The received location will send form the server in the form of
GSM modem and the server will response the position of the
train. The information will be send from the main server with
the location of the train. The control of unmanned railway
crossing is implemented by placing display as well as alarm
indicator in the train so that they can find the each train
location in the same track about few kilometers before the
The AT89C51 is a low-power, high-
performance CMOS 8-bit microcomputer
It has 4Kbytes of Flash programmable and
erasable read only memory (PEROM).
AT89C51 is a powerful microcomputer
which providesa highly-flexible and cost-
• 128 x 8-bit Internal RAM
• 32 Programmable I/O Lines
• Two 16-bit Timer/Counters
• Six Interrupt Sources
• Programmable Serial Channel
• Low-power Idle and Power-down Modes
• Fully Static Operation: 0 Hz to 24 MHz
Modulated IR transmitter
Ambient light protected IR receiver
3 pin easy interface connectors
Up to 12 inch range for white object
Can differentiate between dark and light colours
A relay is an electrical switch that opens and closes
By the control of another electrical circuit it works.
The switch is operated by an electromagnet to open
or close one or many sets of contacts.
It can able to control an output circuit of higher
power than the input circuit.
RF TRANSMITTER &RECEIVER
The transmitter/receiver (Tx/Rx) pair operates at a frequency of 434
An RF transmitter receives serial data and transmits it wirelessly
through RF through its antenna
The transmission occurs at the rate of 1Kbps - 10Kbps
The transmitted data is received by an RF receiver operating at the
same frequency as that of the transmitter.
Highly Reliable for 24x7 operation with
SMPS power supply adapter / Matched
Status of Modem Indicated by LED
Simple to Use & Low Cost
Quad Band Modem supports all GSM
operator SIM cards
It is a specialized type of modem which accepts a SIM
operates over a subscription to a mobile operator
It is used for sending and receiving SMS and MMS
From the mobile operator perspective, a GSM modem
looks just like a mobile phone.
An IR LED, also known as IR transmitter
It is a special purpose LED that transmits infrared
rays in the range of 760 nm wavelength.
It is made of gallium arsenide or aluminium gallium
IR receivers, are commonly used as sensors
18 PIN DIP
Operating Voltage : 2.4V ~ 12V
Low Power and High Noice Immunity
Low Standby Current and Minimum
Built-in Oscillator needs only 5% Resistor
Easy Interface with and RF or an Infrared
18 PIN DIP
8 ~ 12 Address Pins and 0 ~ 4 Data Pins
Easy Interface with an RF of IR
Minimal External Components
Capable of Decoding 12 bits of Information
ANTI COLLISION DEVICE
The Anti Collision Device is a form of Automatic
ACDs have knowledge embedded intelligence
They take inputs from GPS satellite system for
It act as a watchdog in the dark as they constantly
remain in lookout for other train bound ACDs
SEND SMS USING AT COMMANDS
Some advanced GSM modems like WaveCom and
Multitech, support the SMS text mode
This mode allows you to send SMS messages using AT
commands, without the need to encode the binary
PDU field of the SMS first.
This is done by the GSM modem
SENDING THE MESSAGE
To send the SMS message, type the following
SETTING UP THE MODEM
If the modem contains a SIM card with is secured with a
PIN code, we have to enter this pin code first:
CHECK YOUR GSM MODEM SUPPORT
SMS TEXT MODE
To check if your modem supports this text mode, you
can try the following command:
SCOPE FOR ADVANCEMENT
Train information is transmitted
to next station and road traffic